If I had the parts, you would, too. Sorry it happened.

Often, the RD may have a bushing go bad, freeze up and explode. BTDT, but it got into my rear wheel, which cost a lot more to fix. I recommend disassemble the new one as much as practical, lube everything well (I'm still using Slick 50 1-lube on RD's). Good luck on the rebuild and re-ride.

Check the chain rings on that Merlin, as well as your adjustment. If the cage is not too bad, Sheldon Brown says "you can squeeze it back." All depends on the damage, I suppose. If you need to go braze-on, I have a black clamp adapter you're welcome to (28.6)